1. Field of the Invention
The present invention relates to a recess channel transistor and a method of forming the same. More particularly, the present invention relates to a self-aligned recess channel transistor having an inner gate with a center portion that has a smaller width than a protruding upper portion and a lower portion of the gate and a method of forming the same.
2. Description of the Related Art
Conventionally, a recess transistor is used to achieve a higher density as a cell size is scaled down to the sub-micron range. As a planar gate size narrows in a recess transistor, however, short channel effects, junction leakage, and source/drain breakdown voltage become significant issues. Conventional recess gates have several disadvantages. A disadvantage of a conventional recess transistor, for example, is a large gate oxide area, which increases a gate loading capacitance. Additionally, another disadvantage of a conventional recess transistor structure is a deep junction depth, which increases a gate to source/drain overlap capacitance and a bit line loading capacitance. A conventional recess gate structure has a further disadvantage of having a weak photo misalign margin.